The present invention relates to a method and apparatus for surface treatment of such objects as semiconductor wafers.
Among conventional semiconductor wafer film forming apparatus of this type is a wafer surface treatment apparatus, in which a semiconductor wafer is contained in a treatment chamber and rotated while being exposed to a treatment gas atmosphere. The treatment gas thus acts uniformly on the semiconductor wafer surface so as to perform uniform surface treatment.
For example, in the case of a natural oxidation film removal apparatus for removing a natural oxide film formed on the semiconductor wafer, a predetermined liquid, for example, a mixture of hydrofluoric acid and water, is placed at the bottom section of a treatment chamber under normal or raised pressure. The produced hydrofluoric acid vapor is then dispersed within the treatment chamber.
At the upper section in this treatment chamber, the semiconductor wafer is arranged with the surface to be treated faced downwards. While the semiconductor wafer is being rotated, the hydrofluoric acid vapor acts on the semiconductor wafer surface so as to remove natural oxide film.
When surface treatment is performed using for example hydrofluoric acid solvent vapor, since this vapor is corrosive to metals such as heavy metals, the treatment object insertion and removal procedures with respect to the treatment chamber need to be performed without even a minute quantity of treatment gas leakage to the exterior from the treatment gas atmosphere chamber and treatment chamber.
However, in the case of conventional treatment apparatus in which the treatment chamber and a preparatory chamber for insertion and removal are used in common, and the treatment gas atmosphere chamber is provided at the bottom section of the treatment chamber, problems are encountered such as vapor leakage to the treatment chamber and, although in minute amounts, treatment gas also leaks to the exterior.